Chinese antithetical couplets called duì lián (in Pīnyīn) are considered an important Chinese cultural heritage.

Typically, an antithetical couplet includes two phrases or sentences written as calligraphy on vertical red banners, typically placed on either side of a door or in a large hall.

Such couplets are often displayed during special occasions such as weddings or during the Spring Festival, i.e. Chinese New Year. Other types of couplets include birthday couplets, elegiac couplets, decoration couplets, professional or other human association couplets, and the like.

Couplets can also be accompanied with horizontal streamers, typically placed above a door between the vertical banners . A streamer generally includes the general topic of the associated couplet.

Chinese antithetical couplets use condensed language, but have deep and sometimes ambivalent or double meaning. The two sentences making up the couplet can be called the "first scroll sentence" and the "second scroll sentence", or "head" and "tail", or "upper" and "lower".

An example of a Chinese couplet, the correspondence between individual words of the first and second sentences is shown as follows:

海 (sea)天 (sky)

阔(wide) 高(high)

凭(allows) 任 (enable)

鱼 (fish) 鸟 (bird)

跃 (jump) 飞 (fly)

Antithetical couplets can be of different length. A short couplet can include one or two characters while a longer couplet can reach several hundred characters. The antithetical couplets can also have diverse forms or relative meanings. For instance, one form can include first and second scroll sentences having the same meaning. Another form can include scroll sentences having the opposite meaning.

However, no matter which form, Chinese couplets generally conform to the following rules or principles :

Principle 1: The two sentences of the couplet generally have the same number of words and total number of Chinese characters. Each Chinese character has one syllable when spoken. A Chinese word can have one, two or more characters, and consequently, be pronounced with one, two or more syllables. Each word of a first scroll sentence should have the same number of Chinese characters as the corresponding word in the second scroll sentence.

Principle 2: Tones (e.g. "Ping" and "Ze" ) in Chinese are generally coinciding and harmonious. The traditional custom is that the character at the end of first scroll sentence should be tone "Ze". This tone is pronounced in a sharp downward tone just simply non-level tone. The character at the end of the second scroll sentence should be tone "Ping" which is pronounced with a level tone.

Principle 3: The parts of speech of words in the second sentence should be identical to the corresponding words in the first scroll sentence. In other words, a noun in the first scroll sentence should correspond to a noun in the second scroll sentence. The same would be true for a verb, adjective, number-classifier, adverb, and so on. Moreover, the corresponding words must be in the same position in the first scroll sentence and the second scroll sentence.

Principle 4: The contents of the second scroll sentence should be mutually inter-related with the first scroll sentence and the contents cannot be duplicated in the first and second scroll sentences.

Chinese-speaking people often engage in creating new couplets as a form of entertainment. One form of recreation is one person makes up a first scroll sentence and challenges others to create on the spot an appropriate second scroll sentence. Thus, creating second scroll sentences challenges participants' linguistic, creative, and other intellectual capabilities.

The teaching of antithetical couplets was an important method of teaching traditional Chinese for thousands of years.